Vitamin D<sub>3</sub> elicits calcium response and activates blood monocyte‐derived macrophages from patients with vitamin D dependent rickets type II

Two distinct hereditary defects, vitamin D-dependent rickets type I (VDDR I) and type I1 (VDDR 11), have been recognized in vitamin D metabolism. VDDR I is suggested to be a deficiency of the renal 25-hydroxyvitamin D (25(OH)D)-la-hydroxylase. Muscle weakness and rickets are the prominent clinical findings. A normal physiologic dose of la-hydroxyvitamin D, and 1.25-dihydroxyvitamin D, is sufficient to maintain remission of rickets in this disorder. VDDR I1 consists of a spectrum of intracellular vitamin D receptor (VDR) defects and is characterized by the early onset of severe rickets and associated alopecia. This can be attributed to mutations in the VDR gene. Massive doses of vitamin D analogs and calcium supplementation is usually required for the treatment; however, the response to therapy is sometimes variable. Key words25hydroxyvitamin D-1 a-hydroxylase, vitamin D-dependent rickets type I, vitamin D-dependent rickets type 11, vitamin D receptor.Vitamin D is inert when exposed directly to target tissues. It must be hydroxylated to 25-hydroxyvitamin D (25(OH)D) in the liver by a mitochondria1 cytochrome P450 monooxygenase and further la-hydroxylated in the kidney to 1,25-dihydroxyvitamin D (1,25(OH),D), which is the biologically active metabolite. The renal 25(OH)D-Ia-hydroxylase is stringently regulated by various factors. Parathyroid hormone (PTH) activates it in the proximal tubule through a CAMP-mediated pathway, but 1,25(OH),D. calcium and phosphate inhibit it. Then, the hormonal actions of vitamin D occur through the vitamin D receptor-mediated mechanism. In this pathway, two distinct hereditary defects have been recognized. Vitamin Ddependent rickets type I (VDDR I) and vitamin D-dependent rickets type I1 (VDDR 11) are la-hydroxylase deficiency and target organ resistance to 1,25(OH),D respectively, derived from the abnormality in the vitamin D receptor (VDR).

show abstract

Vitamin D‐dependent rickets type I and type II

Takeda

Yamamoto

Taketani

et al. 1997

Pediatrics International

Self Cite

View full text Add to dashboard Cite

show abstract

An update on the therapeutic potential of vitamin D analogues

Stein

Wark²

2003

Expert Opinion on Investigational Drugs

View full text Add to dashboard Cite

The review provides an evaluation of the therapeutic potential of vitamin D analogues in the context of the current understanding of vitamin D biochemistry, molecular biology and physiology. Vitamin D activity results from several circulating and intracellular physiological metabolites acting simultaneously through at least three receptors. Common analogues are reviewed. Although most vitamin D analogues have traditionally been analogues of 1,25-dihydroxyvitamin D, it may be better to deliver high doses of base vitamin or (analogues) of 25-hydroxyvitamin D. This would permit physiological endocrine, paracrine and autocrine vitamin D metabolism. Agonists or antagonists of tissue-specific vitamin D metabolic pathways could be coadministered. The importance of measuring endogenous vitamin D metabolites during in vivo studies and the pitfalls of extending data across species and time are emphasised. Human vitamin D analogue trials should include direct comparison against the related endogenous metabolite.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Vitamin D₃ elicits calcium response and activates blood monocyte‐derived macrophages from patients with vitamin D dependent rickets type II

Cited by 2 publications

References 28 publications

Vitamin D‐dependent rickets type I and type II

Vitamin D‐dependent rickets type I and type II

An update on the therapeutic potential of vitamin D analogues

Contact Info

Product

Resources

About

Vitamin D3 elicits calcium response and activates blood monocyte‐derived macrophages from patients with vitamin D dependent rickets type II

Cited by 2 publications

References 28 publications

Vitamin D‐dependent rickets type I and type II

Vitamin D‐dependent rickets type I and type II

An update on the therapeutic potential of vitamin D analogues

Contact Info

Product

Resources

About

Vitamin D₃ elicits calcium response and activates blood monocyte‐derived macrophages from patients with vitamin D dependent rickets type II